如何从Groovy AST转换访问所有构造函数？

Question

I am writing an AST transformation intended to keep a bidirectional JPA relationship in sync by making the setter on the referenced side also call the setter on the owning side. This works reliably when calling setFoo() , but a variable initialized in the constructor (because of a initializer statement in the declaration, a new in the constructor, or a constructor parameter) won't be linked.

To handle this case, I can open up all of the existing constructors (plus any implicit default constructor) and add the necessary code. However, some common AST transformations that add constructors, such as @TupleConstructor , run in the CANONICALIZATION phase, and there's no phase after that where I can reliably insert new instructions.

How can I ensure that my extra code is added to each constructor, including ones that may be added by other transformations?

Answer 1

The best approach here isn't to alter all the constructors but rather to use an object initializer block, which is copied to the end of all constructors. There's a minor unsafe-publication risk if the cooperating class does something foolish, but it's the same risk as adding the statement to the end of constructors explicitly.

The way to do this is:

classNode.addObjectInitializerStatements(assignS(target, value));